Spray dampeners are commercially available and are used to spray a fountain solution mixed with water on a roller in a printing press, preferably an offset press, in precisely controlled amounts in order i.a. to increase the printing quality and reduce the ink consumption.
It is already known to provide means for controlling the supply of fountain solution mixed with water to the nozzles in dependence of certain factors, such as the operating speed of the printing press. However, if the paper web to be printed in the printing press has a smaller width than the roller sprayed by the nozzles of the spray dampener, the water sprayed on the roller outside the width corresponding to the paper web width may cause disadvantages.
In order to ensure that only a roller width corresponding to the paper web width is fully dampened by the spray dampener nozzles, shutter devices of the kind shown in US-A-4 831 927 (see FIG. 6) may be employed.